This study will examine the neurotoxicity of the vinyl monomer acrylamide in monkeys. Acrylamide is widely used in commercially important polymers, and its neurotoxic properties make it a significant industrial hazard and environmental pollutant. Our previous experimental studies in rodents with this compound, in which we demonstrated its ability to produce central-peripheral distal axonopathy, will be extended to examine by light and electron microscopy and by neurophysiologic techniques: 1) The peripheral and central nervous system damage after chronic (2 1/2 year) exposure of primates to acrylamide at low levels commonly held to be nontoxic, 2) the extent of central nervous system damage after chronic exposure at levels thought to produce only peripheral neuropathy, 3) the ability of the central nervous system to recover from axonal degeneration induced in the primate by acrylamide monomer. The combined morphological and physiological approach will pinpoint the most vulnerable areas of the CNS and will enable us to monitor the nature and degree of recovery in the living animal. The objectives of these studies are 1) to meet some of the Research Needs specified in National Institute of Occupational Safety and Health Criteria Documents for Acrylamide (1976) and elsewhere in the U.S. Environmental Protection Agency reports on Acrylamide (1976, 1977), 2) to determine whether significant brain damage occurs in primates exposed to acrylamide and the most sensitive means of detecting it, 3) to determine whether such damage is reversible, 4) to develop a new, sensitive, non-invasive technique, readily applicable to humans, for assessing subclinical nervous system damage produced by neurotoxins.